It is a known method to distribute video signals from a computer to a plurality of monitors by means of operational amplifying ICs to form voltage amplifing circuit and current amplifing circuit. However, since video signals higher than 100 MHz will attenuate abruptly when passing through an IC, the bandwidth of the known method will be limited. If we use high frequency operational amplifing IC to design, the cost will be increased dramatically. Moreover, an operational amplifying IC needs both a positive voltage source and a negative voltage source, this makes the related circuit more complicated and causes more noises.